Electronic systems and circuits have made a significant contribution towards the advancement of modern society and are utilized in a number of applications to achieve advantageous results. Numerous electronic technologies such as digital computers, calculators, audio devices, video equipment, and telephone systems have facilitated increased productivity and reduced costs in analyzing and communicating data, ideas and trends in most areas of business, science, education and entertainment. Frequently, electronic systems designed to provide these results include integrated circuits. Integrated circuits typically include contact regions for conducting electricity (e.g., between active components) and it is often very difficult to achieve optimized results within requisite narrow tolerances when attempting to fabricate precise contact regions that operate properly.
Semiconductor integrated circuit manufacturing efforts are usually complicated by ever increasing demands for greater functionality. More complicated circuits are usually required to satisfy the demand for greater functionality. For example, there is usually a proportional relationship between the number of components included in an integrated circuit and the functionality. Integrated circuits with more components typically provide greater functionality. However, including more components within an integrated circuit often requires the components to be densely packed in relatively small areas and reliably packing a lot of components in relatively small areas of an integrated circuit (IC) is usually very difficult.
One traditional focus for achieving greater densities has been directed towards reducing the size of individual components (e.g., transistors). The components of an integrated circuit are usually fabricated on a single silicon substrate and maintaining both the integrity of the system as a whole as well as the individual basic device characteristics is very important for proper operation. Proper relational characteristics are very helpful in achieving these objectives and without them there is a tendency for detrimental interactions to occur. Thus, it is important for integrated circuit fabrication technologies to provide an advantageous balance between component integrity and increased component density.
Semiconductor contact formation processes usually include the creation of a contact void for deposition of the contact layer. The contact void creation typically determines the contact configuration. The smaller the void the more compact the contact and the greater the possible component density. However, decreases in contact sizes are usually limited by contact void creation processes (such as lithographic etching processes). Standard lithographic etching and removal processes traditionally have difficulty producing relatively small contact voids. Complex processes that attempt to create smaller voids are often cost prohibitive or nonfeasible.
While decreasing the size of a contact usually permits greater component densities, there are usually physical limitations on how small the contact can become and still operate properly. It is important for contacts to be formed in a manner that ensures proper operation without defects. Interconnection phenomenon such as electromigration can cause reliability problems as the dimension of the contact becomes very small. For example, electromigration can cause discontinuities in conducting materials if the dimensions are too small. Thus, most conducting materials have a critical dimension (CD) that limits how small a contact can be and still operate reliably. Fabrication of small contacts with desirable CD characteristics can be challenging.
It is also important to maintain adequate insulation around the contacts. Without proper component insulation there is a tendency for detrimental interactions between component parts to occur that hinder proper and reliable operation. For example, placement of more components in smaller spaces by reducing the separation between adjacent component parts often increases the probabilities of failures associated with leakage currents. It is also desirable for integrated circuit component formation processes to be efficient and low cost. While introduction of complex and complicated lithographic techniques may attempt to provide small size components, these advance techniques usually consume significant resources and are very expensive. Standard lithographic techniques are usually more efficient and do not require extensive retooling efforts. Therefore, the ability to precisely form semiconductor contact regions in a convenient and efficient manner is often very important.